nixpkgs/nixos/modules/hardware/printers.nix
nyanotech 6a22ce0edf
nixos/printers: fix ensureDefaultPrinter
`lpoptions -d` sets the default printer *for this user*, while `lpadmin -d`
  sets the system-wide default printer.
2021-04-17 12:33:31 +00:00

136 lines
5.2 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.hardware.printers;
ppdOptionsString = options: optionalString (options != {})
(concatStringsSep " "
(mapAttrsToList (name: value: "-o '${name}'='${value}'") options)
);
ensurePrinter = p: ''
${pkgs.cups}/bin/lpadmin -p '${p.name}' -E \
${optionalString (p.location != null) "-L '${p.location}'"} \
${optionalString (p.description != null) "-D '${p.description}'"} \
-v '${p.deviceUri}' \
-m '${p.model}' \
${ppdOptionsString p.ppdOptions}
'';
ensureDefaultPrinter = name: ''
${pkgs.cups}/bin/lpadmin -d '${name}'
'';
# "graph but not # or /" can't be implemented as regex alone due to missing lookahead support
noInvalidChars = str: all (c: c != "#" && c != "/") (stringToCharacters str);
printerName = (types.addCheck (types.strMatching "[[:graph:]]+") noInvalidChars)
// { description = "printable string without spaces, # and /"; };
in {
options = {
hardware.printers = {
ensureDefaultPrinter = mkOption {
type = types.nullOr printerName;
default = null;
description = ''
Ensures the named printer is the default CUPS printer / printer queue.
'';
};
ensurePrinters = mkOption {
description = ''
Will regularly ensure that the given CUPS printers are configured as declared here.
If a printer's options are manually changed afterwards, they will be overwritten eventually.
This option will never delete any printer, even if removed from this list.
You can check existing printers with <command>lpstat -s</command>
and remove printers with <command>lpadmin -x &lt;printer-name&gt;</command>.
Printers not listed here can still be manually configured.
'';
default = [];
type = types.listOf (types.submodule {
options = {
name = mkOption {
type = printerName;
example = "BrotherHL_Workroom";
description = ''
Name of the printer / printer queue.
May contain any printable characters except "/", "#", and space.
'';
};
location = mkOption {
type = types.nullOr types.str;
default = null;
example = "Workroom";
description = ''
Optional human-readable location.
'';
};
description = mkOption {
type = types.nullOr types.str;
default = null;
example = "Brother HL-5140";
description = ''
Optional human-readable description.
'';
};
deviceUri = mkOption {
type = types.str;
example = [
"ipp://printserver.local/printers/BrotherHL_Workroom"
"usb://HP/DESKJET%20940C?serial=CN16E6C364BH"
];
description = ''
How to reach the printer.
<command>lpinfo -v</command> shows a list of supported device URIs and schemes.
'';
};
model = mkOption {
type = types.str;
example = literalExample ''
gutenprint.''${lib.versions.majorMinor (lib.getVersion pkgs.gutenprint)}://brother-hl-5140/expert
'';
description = ''
Location of the ppd driver file for the printer.
<command>lpinfo -m</command> shows a list of supported models.
'';
};
ppdOptions = mkOption {
type = types.attrsOf types.str;
example = {
PageSize = "A4";
Duplex = "DuplexNoTumble";
};
default = {};
description = ''
Sets PPD options for the printer.
<command>lpoptions [-p printername] -l</command> shows suported PPD options for the given printer.
'';
};
};
});
};
};
};
config = mkIf (cfg.ensurePrinters != [] && config.services.printing.enable) {
systemd.services.ensure-printers = let
cupsUnit = if config.services.printing.startWhenNeeded then "cups.socket" else "cups.service";
in {
description = "Ensure NixOS-configured CUPS printers";
wantedBy = [ "multi-user.target" ];
requires = [ cupsUnit ];
# in contrast to cups.socket, for cups.service, this is actually not enough,
# as the cups service reports its activation before clients can actually interact with it.
# Because of this, commands like `lpinfo -v` will report a bad file descriptor
# due to the missing UNIX socket without sufficient sleep time.
after = [ cupsUnit ];
serviceConfig = {
Type = "oneshot";
};
# sleep 10 is required to wait until cups.service is actually initialized and has created its UNIX socket file
script = (optionalString (!config.services.printing.startWhenNeeded) "sleep 10\n")
+ (concatMapStringsSep "\n" ensurePrinter cfg.ensurePrinters)
+ optionalString (cfg.ensureDefaultPrinter != null) (ensureDefaultPrinter cfg.ensureDefaultPrinter);
};
};
}